Desuperheater



DESUPERHEATER Filed Feb. 17, H1955 INVENTOR ATTORNEY Patented June 26, 1934 PATENT FFIC DESUPERHEATER Andr Huet, Paris, France, assigner to The Superheater Company, New York, N. Y.

Application February 17, 1933, Serial No. 657,200 In France November 17, 1932 1 Claim.

The present invention has for its object the provision of a process for desuperheating steam consisting in constantly withdrawing from the desuperheater a suitable portion of the water it contains, this portion being withdrawn from a point adjacent to the level of the water in use so as to provide a continual renewal of this water and constantly eliminating that portion of the water or the foam which shows the highest concentration of dissolved salts, and by this means to keep the concentration of the salts in the water at a predetermined low level thereby avoiding the formation oi deposits and incrustations in the desuperheater.

The following description, which is to be read in connection with the accompanying drawing and which is given by way of example, will make clear how the invention will be put into practice.

In the single iigure there is shown diagrammatically a steam boiler l from whose upper drum 2 a connection 3 serves for taking on the steam, the steam produced being led by the piping 4 to the saturated steam header 5 of a superheater; the steam passing thence into and through the superheater elements 6 and so into the superheated steam header 7.

From there the steam iiows by means of the piping 8 which is provided with a valve 9 into the desuperheater 10. This desuperheater comprises the inlet chamber 11 and the outlet chamber 12 connected by the desuperheater elements 13 located in the drum 14 which contains water coming from the lower drum 15 of the boiler by means of the piping 16. The superheated steam flows Y izes a part of this water.

through the chamber 11, elements 13, into the chamber 12 and thence leaves by the pipe 17. In passing through the elements 13, it gives up a part of its heat to the water in the drum 14 and vapor- The saturated steam thus produced ows through the pipe 18 to the drum 23 where it joins the steam produced in the boiler.

The drum 14 of the desuperheater 10 equipped with a water level indicator 19.

At rest, that is to say when the boiler is not delivering any steam, the water level in the desuperheater will be at the same height as that in the boiler drums in accordance with the principle of communicating vessels. When, however, the plant is in operation, the rate of evaporation per horizontal sectional unit being much greater in the desuperheater than in the drums of the boiler and therefore the mixture of water and steam being less dense in the desuperheater, the

water level 20 in the latter will rise in comparison with the water level in the boiler drums.

Unless the boiler is fed entirely with distilled water, which is rather an exceptional situation, the water of the drum 15 feeding the drum 14 contains a certain proportion of salts. As a result of the evaporation occurring in thedrum 14, the concentration of the salts in the water in this drum constantly increases and results rapidly in deposits of mud and incrustations unless precautions are taken to reduce the concentration. The concentration reaches its maximum at the water level in the drum 14 in the upper layers of water and in the foam produced by the evaporation.

In accordance with the invention, a return conduit 22 is connected into the wall of the drum 14 a little below the water level 20 which is the level assumed by the water during operation. The other end of this conduit is connected into the wall of the drum 23 below the water level in this drum.

As a result of these connections of the conduit 22 below the water levels, a part of the water contained in the drum 14 constantly flows from this drum into the drum 23 together with the salts which it contains so that the water of the drum 14 is constantly renewed and the concentration of the salts in it remains practically equal to the concentration existing in the water of the boiler. This result is ensured by the fact that the water withdrawn from the drum 14 has the greatest concentration of salts.

The return to the boiler of the water withdrawn from the drum 14 has the advantage that the heat contained in it is not lost. It may, however, also be disposed in some other way, its heat in that case either being lost or recovered by any known means.

In the case represented in the drawing the desuperheater is supposed to be of the type stated, that is, with a constant level. The invention, however, is equally applicable to desuperheaters with a variable water level. In that case the arrangement for taking water off from the drum 14 is modified to take count of the varying level by means of a float or in any other known manner.

It is not requisite for the application of this invention that the desuperheater should be fed by water coming from the boiler. It may, if preferred, be fed from some special feed hot well by means of a pump or in any other preferred way. In this case the circulation in the desuperheater is produced by carrying the water which has been removed from a point near the water level obtained during operation back into the feed hot well or even to the boiler. The withdrawal of the water from the drum 14 may also be eiected by means of an automatic blow-off of any known type.

Other modications in detail may be made in practicing the invention without such modications removing the apparatus from its scope.

What I claim is:

In apparatus of the class described the combination of a boiler, a superheater, a desuperheater of the type wherein steam to be desuperheated flows in heat transferring relation to but out of Contact with a body of water and having a free water level, the desuperheater being located at such an elevation that its water level diuing operation will be somewhat higher than the boiler water level, connections to convey steam from the boiler to the superheater, from the superheater to the desuperheater and from the desuperheater to the point of use, a. connection to convey away 'the steam generated in the desuperheater, a connection to supply boiler water to the desaperheater and a further connection extending to the boiler from the point in the desuperheater below its water level during operation but above the Water level of the boiler, whereby there is provided a circulatory system including the desuperheater and the boiler.

ANDRE HUET.

1. ffl 

